Just as the title says, I want a drama where the main lead, preferably male, but not necessary uses rich counterpart for revenge. I would like something along the lines of "Innocent Man" but even shows like "That Winter, The Wind Blows" is also acceptable.

I also like happy endings but is not necessary.
Not exactly revenge, but the lead in High Society cons a Heiress and cruelly uses her for his own devices until it all falls apart, etc.
Bad Guy comes to mind.
I don't know if this is what you're looking for but 'Falling for Innocence' should be right even though the male is technically the rich one. 
My princess. The intention was to seek revenge with female lead included. However, it will soon turn to '...the male lead falling in love and helping her!'

Well, I mean she was a heiress by birth if that doesn't work out I mean Hotel King she was an heiress (Though he never used her for revenge he fell before she did, she becomes penniless in the middle of the series so I think the user is fine with heiress by birth)